The statements in this section merely provide background information related to the present disclosure and cannot constitute prior art.
In order to increase their compression rates, the compression stages of an axial-flow turbomachine compressor are equipped with gasket seals. These seals are applied to the inner surfaces of the outer shrouds and inner shrouds. These seals are made of abradable or friable materials, which are able to erode in the event of contact with the rotor. These seals may come into contact with ends of rotor blades or seal lips without degrading these. It is thus possible to reduce the dynamic clearances at the seals whilst preserving the mechanical integrity of the aerodynamic elements.
The seals can be made of a silicone material that is injected directly on the shroud with the aid of a mould. Such a mould can be fixed even to the stator, and defines a moulding cavity in combination with the inner shroud. The cavity thus formed corresponds generally to the definitive shape of the abradable track, if necessary the abradable track can be machined following demoulding.
Document FR2977521 A1 discloses a mould for injecting an abradable material on an inner shroud of a low-pressure compressor rectifier of an axial-flow turbomachine. The mould makes it possible to inject silicone even at the inner surface of the shroud. The injection is performed with the aid of a fixed mould centred directly on the rectifier. The mould comprises a generally tubular wall placed inside the shroud, and radial annular walls that cooperate with the shroud. The mould, combined with the inner shroud, encloses an annular moulding cavity. The nature of the contact between the mould and the rectifier allows optimal concentricity with the abradable layer. However, the corresponding mould is particularly difficult to handle due to its weight. The cost of the components of the mould constitutes a significant investment on account of the complexity of the mould and of the required fixing means thereof, seals thereof, and centring surfaces thereof. The cleaning of the mould represents a considerable proportion of the usage cost thereof. Also, the shroud can have a deviation of concentricity with the outer shroud, which is reflected by a variation of the thickness of the abradable layer.